Hi, a few days ago i noticed 2 red spots on the tip of the head of this walking catfish. 2 days after there were 3 and they got twice bigger. they are located right on the base of one of his antlers. he is in a 600 liter tank alone with 2 external filter . Beside those spots he is ok , active and eating. Does someone has an idea what are those? are there any disease demonstarting similiar simptoms? The pics i have are horrible, later ill try again with a better camera. thank you